Polymerization of ethylene

Claim 2

A process for polymerizing ethylene or ethylene and at least one α-olefin which comprises contacting ethylene or ethylene and an α-olefin with a catalyst thereby to polymerize the ethylene or the ethylene and the α-olefin, which catalyst comprises a combination of: (A) a metallocene compound of a transition metal selected from the Groups IVB, VB and VIB of the Periodic Table; (B) an aluminoxane; and (C) a silicon compound having an Si-O-C bond.

Claim 3

The process as claimed in claim 1 wherein the metallocene compound is represented by a formula (1): (CpR m ) a R′ b (CpR m ) MX c-(a+1) (1) wherein the moiety (CpR m ) represents cycropentadienyl or a substituted cyclopentadienyl group in which each of R which may be the same or different is hydrogen atom, a monovalent hydrocarbyl group having 1 to 20 carbon atoms or a 4- to 6-membered ring sharing two carbon atoms of the cyclopentadienyl moiety Cp; R′ is a divalent group which links the groups (CpR m ) a and (CpR m ) and which is selected from the group consisting of an alkylene group having 1 to 4 carbon atoms, an alkylisilicon having 1 to 4 carbon atoms in each of the alkyl moiety thereof, an alkylgermanium having 1 to 4 carbon atoms in each of the alkyl moiety thereof, an alkylphosphine having 1 to 4 carbon atoms in each of the alkyl moiety thereof, and an alkylamine having 1 to 4 carbon atoms in each of the alkyl moiety thereof; X each of which may be the same or different from each other represents hydrogen atom, a monovalent hydrocarbyl group having 1 to 20 carbon atoms or a halogen atom; M represents a transition metal of the Group IVB, VB or VIB of the Periodic Table; c represents a valence of the transition metal M, b is 0 or 1; a is 0, 1 or 2, provided that when a is 0, b is 0, when b is 1, m is 4, and when b is 0, m is 5.

Claim 4

The process as claimed in claim 2 wherein the metallocene compound is represented by the formula (1) where M is Zr, Ti or Hf, a is 1, and at least one of X is the hydrocarbyl group or a chlorine atom or a hydrogen atom.

Claim 5

The process as calimed in claim 2 wherein the metallocene compound is represented by the formula (1) where M is Zr, a is 1, and at least one of X is the hydrocarbyl group or a chlorine atom.

Claim 6

The process as claimed in claim 1 wherein the metallocene compound is selected from the group consisting of bis(cyclopentadienyl)zirconium dichloride, bis(cyclopentadienyl)zirconium methylchloride, bis(cyclopentadienyl)zirconium monochloridehydride, bis(methylcyclopentadienyl)zirconium dichloride, bis(ethylcyclopentadienyl)zirconium dichloride, bis(butylcyclopentadienyl)zirconium dichloride, bis(pentamethylcyclopentadienyl)zirconium dichloride, bis(indenyl)zirconium dichloride, bis(4,5,6,7-tetrahydro-­1-indenyl)zirconium dichloride, ethylene bis(cyclopentadienyl)zirconium dichloride, ethylene bis(indenyl)zirconium dichloride, and ethylene bis(4,5,6,7-tetrahydro-1-indenyl)zirconium dichloride.

Claim 7

The process as claimed in any one of the preceding claims wherein the aluminoxane is selected from the group consisting of one having a formula: where R¹ represents a hydrocarbyl group having 1 to 8 carbon atoms and m represents an integer of 2 to 100 and one having a formula: where R², R³ and R⁴ each represent a hydrocarbyl group having 1 to 8 carbon atoms and n represents a number of from 2 to 100.

Claim 8

The process as claimed in claim 6 wherein R¹, R², R³ and R⁴ each represent a lower alkyl.

Claim 9

The process as claimed in claim 7 wherein R¹, R², R³ and R⁴ each represent methyl.

Claim 10

The process as claimed in any one of the preceding claims wherein m and n are each a number of 2 to 50.

Claim 11

The process as claimed in any one of the preceding claims wherein the silicon compound having an Si-O-C bond is represented by a formula: R⁵ 4-n SiY n wherein R⁵ represents a hydrocarbyl group having 1 to 10 carbon atoms, Y represents a group OR⁶ or OCOR⁷ where R⁶ and R⁷ which are the same or different from R⁵ each represent a hydrocarbyl group having 1 to 10 carbon atoms, and n is a number satisfying an equation 0<n≦4, R⁵'s when 4-n is 2 or larger being the same or different from each other.

Claim 12

The process as claimed in claim 10 wherein Y is OR⁶, R⁶ being a lower alkyl having 1 to 4 carbon atoms, and n is a number selected from the group of 3 and 4.

Claim 13

The process as claimed in claim 11 wherein n is 4.

Claim 14

The process as claimed in any one of the preceding claims wherein the process is for producing polyethylene which has an MFR value smaller than that which would be obtained when no silicon compound having an Si-O-C bond is used in the catalyst.

Claim 15

The process as claimed in any one of the preceding claims 1 to 12 wherein the process is for producing an ethylene copolymer having an α-olefin copolymerized therein in a content of up to 20 mol % of the copolymer, while the copolymer has an MFR value smaller than that which would be obttained when no silicon compound having an Si-O-C bond is used in the catalyst.

Claim 16

The process as claimed in any one of the preceding claims 1 to 12 wherein the process is for producing an ethylene copolymer having an α-olefin copolymerized therein in a content of up to 20 mol % of the copolymer, which ethylene copolymer has (1) a density of from 0.85 to 0.94 g/cm³, (2) a melting point or melting points not reaching 120°C determined by a differential scanning calorimetry in accordance with ASTM D3417, and (3) a Q value of no higher than 3.2, the Q value being defined by an equation: Q = M w /M N where M w and M N respectively mean a weight-average molecular weight and a number-average molecular weight both determined by gel permeation chromatography.